Speaker
Description
Observations using the JWST have shown that high-redshift massive quiescent galaxies (MQGs) are both more numerous and form earlier than previously thought. Owing to their high stellar masses and extreme central densities early on in cosmic history (z > 3), they are likely progenitors of the so-called red nugget galaxies at z~2, which in turn are thought to evolve into the cored, massive early-type galaxies that are observed in the present-day universe.
In my talk, I will present initial results from a simulation suite of isolated minor merger series between a MQG and gas-rich and gas-poor satellite galaxies. The simulations utilize the KETJU code in conjunction with a modified version of the GADGET-3 code, enabling fully resolved supermassive black hole (SMBH) dynamics in addition to subgrid recipes for AGN feedback, stellar feedback, star formation, and gas cooling. With KETJU, we are able to track the SMBH mergers down to the gravitational-wave-driven regime and closely follow the central stellar density evolution driven by binary scouring. Using JWST observations, the initial conditions are calibrated to match observed high-redshift galaxies. The MQG host is then evolved from z~5 down to z~2 using multiple merger histories and AGN feedback recipes, with the final merger remnants being in good agreement with observed z~2 red nuggets.